1. Field of the Invention
The present invention relates to boring heads for rotary tools, and, in particular, to boring heads with imbalance compensation.
2. Description of the Related Art
Boring heads with a fine adjustment mechanism for the tool support and a counterweight mounted in the tool body for imbalance compensation are used primarily for machining bores with close tolerances and, for this purpose, can be mounted in a spindle driven in rotation. Current technical development is now aimed at using increasingly better and above all harder and more heat-resistant cutting materials and at operating at increasingly higher revolutions per minute (rpm). Since movable single-edge boring heads are not rotationally symmetrical due to their design, they will be imbalanced to a greater or lesser degree. This can cause vibrations in the machining system which have an unfavorable effect on the bores. In particular, the dimensional accuracy and shaping precision as well as the surface quality suffer due to such vibrations. In addition, the service life of the cutting material is strongly reduced.
The state of the art includes numerous proposals for compensating for the imbalance on a boring head. For example, German Patent No. DE-C 35 10 259 discloses a rotating fine boring head for a tool machine in which, on the circumference of the tool head, two weights are mounted which are connected by a cable line and are moved via a graduated ring.
German Patent No. DE-C 42 42 063 discloses a boring tool in which automatic imbalance compensation is provided. For this purpose, a two-armed transmission lever is mounted in the tool body which, with one arm, engages a driving carriage and, with the other arm, a tool carriage. Upon the displacement of the driving carriage, the tool carriage is also moved in the opposite direction. The imbalance compensation here takes place automatically and depends on the diametral displacement.
The present invention has the objective of designing a boring head of the type mentioned above which is especially well suited for high rotation speeds and makes a more compact design possible. Further aspects and advantages of this invention will become apparent from the detailed description which follows.